1. Field of the Invention
The present invention relates to a switch device and, more specifically, to a compact switch device having a push button with a long stroke.
2. Description of the Background Art
Compact switch devices which are turned ON/OFF by manual operation have been used in input devices of personal computers such as keyboards, digitizers, mouse, in telephones, audio/video equipment, in remote controllers of electric buses, and so on.
FIG. 1 is a perspective view showing such a conventional switch device FIG. 2 is a perspective view showing, in-explosion, the switch device of FIG. 1. Referring to FIGS. 1 and 2, a conventional compact switch device comprises a push button 71, a switch body 72 which is a mechanical key switch which is turned on/off in correspondence with the pressing of the push button 71, and a switch base 73 holding these elements unitary.
The push button 71 comprises a box shaped button body 71a. The lower surface of the button body 71a is opened, and engaging holes 74 are provided on both side surfaces. The switch body 72 has a plunger 72a provided projecting from the upper surface and capable of being pressed, a switch mechanism therein corresponding to the plunger 72a, and terminals 77 extending downward at lower four corners. The switch base 73 is a box with four notched corners having engaging pawls 75 projecting outward on both side surfaces.
The switch body 72 is fitted in the switch base 73 to be fixed with the four terminals 77 extending downward from the notched portion 76 of the switch base 73, and the push button 71 is put thereon. The engaging pawls 75 of the switch base 73 are engaged with the engaging holes 74 from the inside of the button body 71a. The compact switch device is structured in this manner.
Recently, such switch devices have been further reduced in size, and the stroke of the push button has become as short as about 0.3 mm, accordingly. Therefore, when a person operates such a switch with gloves on, it is difficult to determine whether or not the push button is surely pressed.
In addition, in such a switch device, the push button moves from the OFF position to the ON position by external pressing force. However, when the ON/OFF switching occurs, the push button contacts with a stopper, so that further movement of the button is prevented. Therefore, when a person hits the push button with his finger, he receives shock on his fingers. When one operates an operation panel having such switches for a long period of time, his fingers become fatigued.
In the prior art, the switch body 72 is simply inserted in the switch base 73 when the switch structure is assembled. Therefore, sometimes the switch body 72 is disconnected or goes out of the base 73, so that the assembling operation of the switch structure is.not very effective.